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East Pacific/2015/03E/Archive/11
Public advisory TROPICAL STORM CARLOS ADVISORY NUMBER 11 WIKI-HURRICANES FORECAST CENTER 400 AM CDT SAT JUN 13 2015 ...CARLOS POORLY ORGANZIED... SUMMARY OF 1000 PM CDT...09:00 UTC...INFORMATION ----------------------------------------------- LOCATION... 14.7N 100.4W ABOUT 145 MI... 250 KM SSW OF ACAPULCO, MEXICO MAXIMUM SUSTAINED WINDS...50 KT...70 MPH...105 KM/H MINIMUM BAROMETRIC PRESSURE...992 MB...29.32 INCHES PRESENT MOVEMENT...STATIONARY DISCUSSION AND 48-HOUR OUTLOOK ------------------------------ At 1000 pm CDT, the center of Tropical Storm Carlos was located at 14.9N, 100.1W, or about 145 miles (250 km) south-southwest of Acapulco, Mexico. Maximum sustained winds were 60 knots (70 mph, 105 km/h), with higher gusts. The minimum barometric pressure was 992 millibars (hPa; 29.32 inHg), and the system is stationary. Little change in strength is forecast tomorrow, but there is a strong likelihood that Carlos becomes a hurricane on Sunday. A Tropical Storm Watch is in effect for... * Acapulco to Punta San Telmo NEXT ADVISORY ------------- Next complete advisory at 1000 am CDT. $$ Forecaster YE Discussion TROPICAL STORM CARLOS DISCUSSION NUMBER 10 WIKI-HURRICANES FORECAST CENTER 400 AM CDT SAT JUN 13 2015 Several hours ago, Tropical Storm Carlos was a somewhat sheared tropical cyclone. The convection is elongated north to south, and the convection is displaced SE from the center, though this system has become better organized in the most recent few frames, but at that same time, convection has waned somewhat. The reason for the initial struggles is because of the 10-15 knts of northerly shear, possibly stronger, which had been toying with Carlos for its entire life may be weakening. This may also be in the process of building an inner core as radar imagery several hours indicated the eye is open to the north side, though since then, it may be starting to appear in visible imagery. Latest intensity estimates from SAB are T4.0/65 knts (largely based on the recent increase in banding features) and current intensity values from TAFB are T3.5/55 knots. As of 8z, CMISS ADT (8.2.1) numbers were T3.7/59 knts, while SSD ADT (8.1.4) were 3.6/57 knts. Therefore, the intensity is elevated at 60 knts, though this could be generous. Unlike a couple days ago when models were trending left, the guidance has shifted right in recent runs. The 18z GFS brought a powerful Carlos onshore near Michoacán by day four. The 0z GFS has a much weaker Carlos hitting Jalisco as a tropical storm between day 4 and day 5. The 18z HWRF also brought ashore near Colima. The GFDL, of course, has an eastward bias, and continues to insist on slamming the system offshore. The 0z ECMWf, however, keeps the core offshore, but later has a landfall near Yuma by day 9 as a decaying system. In the short-term, Carlos is expected to remain generally stationary over the next 24 hours or so as it feels the effects of a weakness across the northern Gulf of Mexico; thereafter, a ridge offshore Baja California Sur is expected to build eastward and force the cyclone on a west-northwest trajectory. By the end of the period, a weakness across the Southwest United States generated via trough may provide a gateway for Carlos to move northwest toward, and how much of a weakness will occur remains a big questions, and cause for much uncertainty. The new track is similar to the TVCE consensus, and brings Carlos very close to the Mexican coast. Just when it appeared the intensity forecast was becoming simpler, the latest track shifts have made it complex again. Light to moderate (but diminishing) wind shear should hold this in check for 24 hours, and even the new forecast shows only minor intensification. Following the highly anticipated significant drop in shear, rapid intensification becomes a possibility, but even the aggressive GFS has backed off of it, and it is a bit puzzling why the models do not depict it. The HWRF shows quite a bit of upwelling to 18C-20C, which seems unlikely, though some upwelling is certainly possible in the short-term. Furthermore, the humidity values will be steadily declining per the SHIPS model, but if the cyclone has a well-defined inner core, the system should be able to mix out the dry air, as somewhat indicated by the GFS model. The upper-level environment could be a bit too warm for my liking as indicated by the SHIPS model, but given the low wind shear and very warm waters, overall thermodynamics are not a serious cause for concern. Given the uncertain track, land interaction could also become an issue after 60 hours, but threat still leaves around a 36 hour window for steady intensification. The new intensity forecast is a bit higher than the previous one and somewhat disregards the underperforming intensity guidance. After 60-72 hours, the intensity forecast largely depends on track. Assuming the below track verifies, one would expect only gradually weakening as part of the core is disrupted by the hurricane, similar to what was observed by Hurricane Alma in 1996. However, if the storm moves inland, rapid weakening is more likely. On the other hand, if the core of the system stays offshore, Carlos could get a bit stronger than shown below, largely since it will have more time to intensify. Users are reminded to not focus on the exact track, since whether or not the center moves ashore could result in major differences in the intensity forecast and any deviation to the right of the track could bring the eye of Carlos ashore. Initial 14.9N 100.1W 60 knts 12 hr 15.2N 100.4W 60 knts 24 hr 15.5N 100.7W 60 knts 36 hr 15.7N 100.9W 65 knts 48 hr 16.1N 101.5W 70 knts 72 hr 17.0N 102.5W 75 knts...Near coast... 96 hr 18.5N 103.8W 65 knts...Near coast... 120 hr 20.2N 105.6W 55 knts...Near coast... $$ Forecaster YE